1. Field of the Invention
The present invention relates generally to laser welding and cutting systems, and more particularly, to a transparent pressure foot for use with laser welding and cutting systems and the like.
2. Description of Related Art
Lasers have numerous uses in manufacturing. Because of their ability to concentrate large amounts of energy to a small point, lasers are particularly well suited to cutting and welding operations. For example, laser welds have been found to result in a high strength weld. This results from high cooling rates due to low energy input per unit length of the weld, which is characteristic of lasers. Another advantage is that a laser weld often results in a purification of the fusion zone. Studies of laser welds show increases in hardness, tensile strength, impact energy, decrease in inclusion content, and oxygen and nitrogen content, as compared to the base metal. In addition, often the necessity for a filler material is avoided by using laser welding. Further, in spot welding, laser welding has the advantage of one side access, as opposed to the two side access required in conventional spot welding. Also, the laser spot weld is stronger and may often be leak tight.
Although the benefits are numerous, some difficulties are encountered in using lasers for welding and cutting. In particular, in those applications where a clamp or pressure foot must be applied to a material before the laser is applied, the clamp must be provided with a window, to permit the laser beam to reach the material. This window creates areas where no clamping takes place. In systems where the continuous application of pressure to the material is critical, for example, where two overlapping materials are to be joined by a laser, this window may allow a gap to exist because no pressure is applied where the window is. Also, the window must necessarily be relatively wide due to tolerances required and to the width of the laser beam above the focal point. A further problem with such windows, is that they generally extend over a limited linear distance, and thereby prevent the formation of a continuous weld.
Thus, one object of the present invention is to provide a means for applying laser energy as well as pressure to a surface at a given point. It is another object of the present invention to provide a means for producing laser welding or cutting in a material that is clamped without the use of a windowed clamp. It is another object of the present invention to provide a laser welding system that permits a relatively long and continuous weld in a clamped surface and that is not interrupted by the confines of a window in the clamp.